Maltreated adolescents involved with the child welfare system (CWS) have typically encountered a host of early adverse experiences, including prenatal exposure to drugs and alcohol, neglectful and abusive care, and repeated caregiver transitions. Consequently, the rates of alcohol use and abuse are significantly elevated among these adolescents. Despite extensive documentation of increased alcohol use among maltreated adolescents, there are limited research findings to guide the development of targeted preventive intervention services for this population. Thus, consistent with the objectives of PA-10-255, the proposed study is designed to investigate the impact of specific early adverse experiences and the cognitive processes underlying behavioral regulation (i.e., risk taking and inhibitory control) on the developmental trajectories of alcohol use in maltreated adolescents and nonmaltreated adolescents. It has been argued that behavioral regulation is influenced by the activity of two neural systems-the ventral striatal system underlying risk taking and the prefrontal system underlying inhibitory control-and that a maturational imbalance between these neural systems contributes to the dramatic increase in alcohol use in adolescence. We will examine the developmental trajectories of risk taking and inhibitory control across adolescence and will investigate the impact of these cognitive processes on early-onset alcohol use in maltreated adolescents and their nonmaltreated peers. Because behavioral regulation is believed to underlie a number of externalizing problems, we will also determine whether deficits in these cognitive processes are related to early-onset alcohol use specifically or to externalizing problems more broadly. In addition, our prior research findings have shown that specific dimensions of early adverse experiences (e.g., severity of physical neglect and number of caregiver transitions) are associated with alterations in key neurobiological systems. Hence, we will investigate the impact of specific early adverse experiences on the developmental trajectories of risk taking, inhibitory control, and early-onset alcohol use. To accomplish these aims, we will assess risk-taking propensity and inhibitory control ability (via adolescent report, caregiver report, and behavioral and electrophysiological performance on tasks that activate specific neural systems) and early-onset alcohol use (via adolescent and caregiver reports) in 150 maltreated adolescents involved with the CWS and 150 low-income, nonmaltreated adolescents. We will collect four waves of data from early (12-13 years) to middle (15-16 years) adolescence to examine the developmental trajectories of risk taking, inhibitory control, and alcohol use across this critical period. The results of the proposed study will pinpoint specific cognitive processes to target in future preventive intervention services for the CWS and other at-risk populations. Additionally, these results will aid in the early identification of the maltreted adolescents most at risk for early-onset alcohol use.